This study of problem solving and conceptual tempo had two objectives: (1) to begin to clarify the underlying deficiencies which contribute to the less efficient information processing of impulsive children (as compared with reflective children) during problem solving; and (2) to demonstrate the utility of using a task analysis as a clinical-research strategy for analyzing cognitive performance deficiences in children. A task analysis was conducted to identify sources of inefficient performance on the Neimark-Lewis pattern matching problem among children aged 7, 9, and 11 years. Data indicated that failure to adequately retain orienting instructions, failure to formulate an efficient solution strategy and failure to consistently implement an efficient strategy once formulated all represented potential sources of performance inefficiency. Conceptual tempo was not associated with failure to retain task instructions. However, "reflective" children were more likely than "impulsives" to formulate high quality solution strategies and consistently implement such strategies once formulated. These data appear to contribute to the clarification of the cognitive mechanisms underlying reflectivity and impulsivity. The task analysis diagnostic procedure yielded an individual "deficiency profile" for each child, thus demonstrating its potential clinical-research utility for analyzing cognitive performance deficits in children. (Author/MS)